ATL / WTL / STL

float pi = 3.1415;
int i_pi = pi; //<-- In VS6, you'd get no warning (usually) but in the newer versions, you'll get a warning about possible loss of data (just to make you more aware of what you are doing)

int i_pi = (int) pi; //<-- No more warning, you've explicitly stated this is what you want.

WndBase
    Dialog : virtual public WndBase
        DialogBase : public Dialog, public CDialog

    GridBase : virtual public WndBase
        GridDlg : public DialogBase, public GridBase
            ValveSummaryDlg : public GridDlg

ON_BN_CLICKED(IDC_RADIO_SUITABLE, &ValveSummaryDlg::OnCheckShowAll)

DialogBase : public CDialog, public Dialog //<-- Change order so CDialog class comes first

#define ON_BN_CLICKED(id, memberFxn) \
	ON_CONTROL(BN_CLICKED, id, memberFxn)

#define ON_CONTROL(wNotifyCode, id, memberFxn) \
	{ WM_COMMAND, (WORD)wNotifyCode, (WORD)id, (WORD)id, AfxSigCmd_v, \
		(static_cast< AFX_PMSG > (memberFxn)) },

class CMyBaseDialog : public CDialog
class GridBase                                         //<-- No real need for WndBase
class GridDlg : public CMyBaseDialog, public GridBase  //<-- First inheritance is directly derived from CDialog